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Ferric iron in Al‐bearing post‐perovskite
Author(s) -
Sinmyo Ryosuke,
Hirose Kei,
St. C. O'Neill Hugh,
Okunishi Eiji
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl025858
Subject(s) - perovskite (structure) , ferrite (magnet) , tetragonal crystal system , materials science , phase (matter) , analytical chemistry (journal) , basalt , hydrothermal circulation , ferric iron , oceanic crust , geology , mineralogy , metallurgy , crystallography , subduction , chemistry , geochemistry , composite material , ferrous , paleontology , organic chemistry , chromatography , seismology , tectonics
The Fe 3+ /ΣFe ratios in both (Al, Fe)‐bearing MgSiO 3 post‐perovskite phase and Ca‐ferrite‐type Al‐phase, synthesized in a natural mid‐oceanic ridge basalt (MORB) composition at 113 GPa and 2240 K, were determined by electron energy‐loss near‐edge structure (ELNES) spectroscopy. The results demonstrate that post‐perovskite has high proportions of Fe 3+ with Fe 3+ /ΣFe ratio of 0.65 ± 0.04. The high Fe 3+ concentration in post‐perovskite may have significant effects on its physical properties, phase stability, and iron partitioning. In contrast, the Ca‐ferrite‐type Al‐phase, which is the second Fe‐bearing phase in a subducting MORB crust, is enriched in Fe 2+ rather than Fe 3+ with Fe 3+ /ΣFe ratio of 0.15 and 0.29.